tekfal23

Is there a difference in the diameter of the hub for a Hydromotive qIV for a Bravo, and a qIV for an outboard or an Alpha? I have a set of qIV's and the hub is much smaller than it is on my Mirage Plus'. I don't mean the shaft size, I mean the actual hub. The Mirage Plus hub is the same diameter as the gearcase on my bravo, but the Hydromotive is quite a bit smaller. Help!!!!

throttleup

You probably have a Quad IV OT (over through) prop. It is designed for the exhaust to exit both through and over the hub. Typically used for outboard applications. The diameter is smaller on the OT vs the through hub Quad IV.

The part number should have OT in it indicating it is in fact the Quad IV OT.

tekfal23

The props are a bit older, but they don't have o/t or anything on the hub. I'd have to go look, but I know they say
HC CL23L Q-IV, No o/t. Could they still be O/T's? How would an OT prop run on a boat without any through prop exhaust?
I also saw a qIV on ebay that looks like it may have a smaller hub on it, but it has some sort of ring on the end of the prop that butts up against the gearcase that looks like it fills in the void between the size of the hub and the size of the gearcase. Is this a common thing, and if so, do you know where I can get one? Thank you for your help!

throttleup

The ring on the hub does fill the void between the gear case and the lower unit. You can contact Hydromotive if you need one for your prop. They are a press fit and made of aluminum.

Matt

tekfal23

Do you think the performance will be compromised with the smaller hub on a bravo?
Can I get the ring from you?

throttleup

The problem may be the diameter, the small can props have a 14 3/4" diameter vs 15 1/2 for the larger diameter hub. We don't normally stock the Hydromotive rings, when needed we sometimes make them.

Matt

tekfal23

So you wouldn't be as worried about the hub size as opposed to the diameter of the prop? What if I'm over-pitched just a bit anyway? That could help keep my revs up.